6G Celicas Forums

The laws of fluid mechanics state that Q(flow)=V(centerline velocity)*A(cross sectional). The A of his current set up with the small D = 3564.7mm^2 . The A of the desired set up is 3959.2 mm^2 . it's 90% of the area. Assuming for instance the engine needs .5 m^3 of volume and we use the standard diameter for reference, it looks like

.5 m^3 = Vc * .003959m^2 where Vc = 126.288 m/s
What we find from fluid mechanics as well is that the velocity of the center of a pipe is faster in the center than it is at the edge. In fact at an incrementally small (.01mm) the velocity is effectively 0. This then means that if you take the radius/2 aka D/4, the velocity would be about 63.144 m/s. The relationship is nearly linear from the center to NEARLY the edge as seen here graph of velocity

In the current setup with the maf in the middle with our hypothetical Q of .5, our Vc is .5=Vc(.003564) meaning Vc(actual) = 140.264 m/s with this linear relationship in mind we know that in a right triangle with the x being the radius, 33.685 and the y being the Vc at 140.265, we find a hypothetical angle of 76.496 degrees. Taking this same angle and applying a new y of the the desired 126.288 we get 126.288/tan(63.152) = 30.328 mm.
This all means that in his CURRENT set up, the appropriate location of his maf in that apparatus is 33.685-30.328 = 3.356mm closer to the edge of his tube.
That would THEORETICALLY be the location for his maf such that his motor would not run rich.
I'm just trying to provide a little bit of SOLUTION instead of more problems

So if you want to use that configuration you should get a about a 3.3-3.5 mm shim to shim your maf sensor holder out a little bit more.
Hope this helps you

Just a little bit of engineering to help solve a problem.

you're right to want to apply some math to a problem like this but why go through all that hand calculation for only one iteration when you could just model it in solidworks in 5 min and run a flow sim. Much easier imo

I look on building a cold air intake in the future. I want the filter sitting in the front left highbeam headlight with a box surrounding it like some gt4 members have already done. That's why I'm looking for the perfect aftermarket maf adapter. I know if I get my hands on on hks with Apexi filter in the future and a sard then I'll be able to see which one gets the best power. And as I stated before we only get crummy 91 octane here in Cali as best pump fuel.

I"ll be borrowing the AEM Air/Fuel Ratio tomorrow from my friend to see if there's a true difference in that adapter you have me roberto and the one I bought a few days ago. I'm also going to get that air box that sits inside of the left fender. So it'll be true cold air and see stock air/fuel ratio. Fuel octane has nothing to do with air/fuel ratio as tested before.

I"d say its a powerful powerplant with good amount of torque. This engine back in the late 1990's was good.

Nothing wrong with the stock oem box (I'm starting to feel that its the best setup), I just love the screaming noise of the short ram intake

This post has been edited by BonzaiCelica: Oct 3, 2011 - 1:22 AM

then sell me your box... lol, dont get so desperate and be patient.

You want to center the maf, grap a piece of plastic, and cut it and rubber sandwich and put it between maf and adapter...

here is the filter ans part number


http://www.jps-trading.com/product_info.php?products_id=801

just dont use the mushroom filter as i have been told is crap/

I was not in the engineering lab nor was I at home Otherwise I would have. Those calculations only took me 5 min anyway. Th write up is what took the time lol

But its simple fluid mechanics, I was just trying to tell people that with PROPER ANALYSIS, solid works or others, you should be able to locate the maf in ANY size intake pipe......theoretically. The same principles are really the reasons why I'm not sold on 3 inch exhaust and 3 inch intakes unless you can PROVE that either ore "chocking" the engine out. Less restrictive CAT, sure, because the engine has to force the exhaust through that. But otherwise, flow in = flow out. It just moves at a slower velocity with a larger pipe.

But I digress. my own beams swap will be going on this winter/spring so I'm sure I'll have my own set of problems then and be asking the same guys for help haha. But the intake doesn't scare me...

This post has been edited by ricochet1490: Oct 3, 2011 - 9:33 AM

so if i understand your math/fluid dynamics lecture up there, not only does the fact the pipe is smaller cause the MAF to read higher, but the fact that its more centered than stock does as well?

the MAF works by measuring the "cooling" effect the flowing air has on a heated wire, so i imagine faster air = more cooling effect.

nice input everyone. I did some testing today with new maf housing with the following air/fuel ratio :

Rod Millen Motorsport Metal 67.4mm inner diameter adapter = 10.4

Ebay Intake (which is currently still for sale online) with 71.4mm inner diameter = 10.9

OEM Intake with 71mm inner diameter = 11.1

Power felt the best with the oem setup also because I was sucking up cold air from the fender area.

now trying to see if I can find a 75mm intake setup so that I can lean out more....

This post has been edited by BonzaiCelica: Nov 20, 2013 - 9:27 PM

Haha sorry for the lecture. But yes, centerline velocity is always faster than the velocity of the fluid cloer to the wall. I don't know how close to center that the stock location is. But (as I just learned) if its about cooling of a wire, yes the more centered it is the more heat would theoretically transferred away. The linear relationship still exists though. so if we could figure out the stock location exactly, we could figure out where to put it in an aftermarket setup.
The ultimate goal would maybe be (once we know specifics about the stock) to make or reccomend a setup with specific location for the maf with something common like 3 in. intake pipe, or the SARD pipe (if it's any different etc)

I have a stock beams intake. what are you after??? I'm looking into an Apexi of Fujita 75mm inner diameter cone filter.

how far is the center of the maf on the stock intake pipe from the tube wall? That's what I need to know. Once the calculation is done and some simulation done as well to prove the theory, the final result should be stickied or something because this is something that 98% of beams swappers struggle with. For my own sanity... are you trying to get an aftermarket intake because of the sound or because of the "power" gain? You have the luxury that most people do not have. You've got the stock intake, this work is primarily going to bge done for those who do not have the stock intake and can't get it....
but let me know what the measurement is to your best guess. Maybe a pic of what it looks like

Thanks
Trace

ps. the calculations I first did may have been for Vaverage instead of Vcenter. So the math may be a little off, as far as spacers are concerned, but the concept still exists.

This post has been edited by ricochet1490: Oct 4, 2011 - 5:52 PM

could of swore I posted it here. Turns out i only posted it on the beams forums, but here it is :



I'm looking to lean out as much as possible so that I use less fuel and gain more power. I know this can be tuned with an standalone ecu but I don't want to spend the money on that right now. I'm also looking to build an intake that sits directly in front of the left highbeam headlight like so. Actually I can't find the link, but if I can place then cone filter directly where the headlight sits then that's even better. I plan on removing the battery from it place and building a cold air intake box their with wind feeding directly through the high beam left headlight.



This post has been edited by BonzaiCelica: Oct 4, 2011 - 6:27 PM

ok, what do you think your micrometer would say the distance is from the inside part of the tube to the center of that sensor? hard to guess here but i'd say about 64mm?

say what???? use paint and edit my picture with some drawings on it so I can understand you....

From the middle of that sensor to the outside wall.

This post has been edited by SwissFerdi: Oct 5, 2011 - 11:34 AM

I need to know what the distance is from the center of the maf to the wall of the tube. Similar to the picture where you showed that the inside diameter was 67.35mm or whatever, how many mm is it from the center of the sensor to the tube wall.

I did this measurement very long ago and I believe its posted on the first few pages, or its probably on the beams forums: but half of 71 mm is 35.5mm. which is your center point.



I'm also looking at a Fujita 3.5 inch inner diameter filter or an Apexi 3.34 inch inner diameter filter. I'll probably go with the Fujita because of pricing. Also talked to the guy who sold me the 67mm afm adapter, and he makes 80mm AFM adapter that he used on 1UZFE engines. I'm willing to try anything at this point. Unfortunately I can't return my 67mm adapter but it will only cost me $60 for the 80mm adapter.



My reason for going with a apexi or fujita filter demonstrated to the above illustration.

This post has been edited by BonzaiCelica: Feb 25, 2013 - 4:24 PM

Not what I want to know. I need a new picture. Where one point of your micrometer is on the center of your maf. The other on the inside part of the tube. How close is the sensor to the wall? Can anyone else with the stock airbox provide this info.

Ok so I turn the maf sensor around so its pointing in the opposite direction and measure it like that? so your talking about the whole sensor as a whole ??



This post has been edited by BonzaiCelica: Oct 6, 2011 - 12:30 AM

It sounds like he's wanting the radius? which is just half the diameter... 71mm ÷ 2 = 35.5mm

naw Rusty because I posted that before. you can even see the picture of the inner diameter of the original oem maf housing.